Answer:
EDIT:
10 feet for every second
Explanation:
Find a dotted point
Locate the x and y, or attitude and seconds in. This case
So we know 60 ft in 3 seconds
So we know the slope is one so go down 1 right 1
That would put us at another point that is not dotted but its on the graph
So its 50 feet in 4 sec
So we know its 10 feet per sec